U.S. Pat. No. 4,096,453 uses dual modes to stabilize an oscillator. However, it differs from the present invention in that it uses transmission line resonators rather than a cavity; it uses only even and odd TEM modes, not TE.sub.11p and HE.sub.11.delta. degenerative modes; and it does not suggest the use of dielectric resonator elements. The device described in this reference obtains a lower Q and lower temperature stability than the oscillator of the present invention.
Ishihara et al., "A Highly Stabilized GaAs FET Oscillator Using a Dielectric Resonator Feedback Circuit in 9-14 GHz", IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-28, No. 8, August 1980, pp. 817-824, in FIG. 13 and accompanying description showns dielectric resonators in a dual mode feedback circuit of an oscillator. This reference differs from the present invention in that it requires two dielectric resonators rather than one; the second dielectric resonator is a band reject filter, not a bandpass filter; and both of the resonators are excited magnetically rather than electrically.
U.S. Pat. Nos. 4,079,341, 4,307,352, 4,321,560, and 4,325,035; Japanese Kokai 54-126450; and Mori et al., "A Highly Stabilized GaAs FET Oscillator Using A Dielectric Resonator Feedback Circuit in 9-14 GHz", Technology Growth for the 80's: 1980 IEEE MTT-S, International Microwave Symposium Digest, 28-30 May 1980, pp. 376-378, show dielectric resonators used in feedback circuits to stabilize oscillators. However, all of these references show single mode stabilization, rather than dual mode stabilization as provided by the present invention. Compared with these six references, the present invention offers better temperature compensation, improved phase noise performance, and a wider range of frequency deviation when electronic varactor tuning is used.